Irrational clue found in abyss (10,3)
I believe the answer is:
bottomless pit
'abyss' is the definition.
(I've seen this in another clue)
'irrational clue' is the wordplay.
I cannot really see how this works, but
'irrational' could be 'pi' (an irrational number) and 'pi' is present in the answer.
This explanation may well be incorrect...
'found in' is the link.
Can you help me to learn more?
(Other definitions for bottomless pit that I've seen before include "nether regions - with 7a" , "place needing it eternally" , "Source of infinite fuel" .)